Firearm with gas operated breech block unlocking means



J. D. MASON sept. zo, 1966 FIREARM WITH GAS OPERATED BREECH BLOCK UNLOCKING MEANS 2 Sheets-Sheet 1 Filed June 14, 1965 INVENTOR JAMES D. MASQ/v PMM/11M, Paf/w, ,P/ffk. ff e* Ufff/r NW @wd J. D. MASON Sept. 20, 1966 FIREARM WITH GAS OPERATED BREECH BLOCK UNLOCKING MEANS Filed June 14, 1965 2 Sheets-Sheet 2 vm mm om MN INVENTOR.

JAMES D. [V1/)50N l1.......mt.-l

.MME

United States Patent Office 3,273,460 Patented Sept. 20, 1966 The present invention relates to firearms and more particularly to the type in which the gas generated during the firing is utilized to actuate mechanism for unlocking the breech block from the breech end of the gun barrel and/or the ejection of the empty cartridge case from the firearm.

The firearm of the present invention comprises means forming a frame and a gun barrel supported by the frame. An orifice and preferably a series of orices are disposed between the breech end and the muzzle end of the barrel. Means is provided forming a chamber which surrounds the barrel and which is in communication with the orifices for receiving gas from the barrel. This latter means includes a part which is movable rearwardly by expansions of gas in the chamber and impingement of gas on the aforementioned part.

The breech end of the gun is provided with a breech block locking element. A breech block is slidably and turnably carried by the aforementioned movable part and the breech block is provided with a locking element which, when the breech block is turned, in one direction, it is locked lwith the locking element of the barrel, and, when turned in the opposite direction, it is unlocked from the locking element of the barrel. An element ils actuated by the aforementioned movable part, upon firing of the gun, for first turning the breech block to unlock it from the breech locking element of the barrel and for thereafter shifting the breech block rearward whereby the spent cartridge case can be ejected from the gun.

More specifically, the breech block includes a spirally shaped cam and the aforementioned gas moved part includes a cam actuator which cooperates with the cam for turning the breech block. A lost motion connection is provided between the said movable part and breech block, whereby the breech block is not moved rearwardly until it is turned, by cam action, to unlock it from the locking element on the barrel.

A spring is compressed when the aforementioned gas moved part is moved by the expansion of the gas, whereby after the energy is expended in moving the movable part, the said part is moved forwardly to breech block closing position.

Still more specifically, the present invention is illustrated in a forty-five Colt pistol wherein a cylinder surrounds the gun barrel and is fixed to the slide. The orifices in the gun barrel communicate with the interior of the cylinder for moving the latter and the slide rearwardly by the expansion of gas within the barrel.

The slide is provided with a cam actuator in the form of a pin which rides in the spiral groove. A longitudinally extending groove also is provided in the breech block for receiving another element fixed to the slide. This latter groove forms a forwardly extending shoulder and a rearwardly extending shoulder. Thus said latter mentioned element and the shoulders provide a lost motion connection between the slide and the breech block whereby, when the slide is moved rearwardly, the breech block effective to turn the breech block to lock the same with the breech.

Other features and the advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the invention is illustrated.

In the drawings:

FIG. l is a left side View of the firearm, the upper part thereof being shown in section, the view showing the slide, the cartridge and breech block in firing position;

FIG. 2 is a view similar to FIG. 1, but showing the slide and the breech block in their rearmost position and showing a spent case being ejected;

FIG. 3 is a view, in longitudinal cross section, of the stationary piston forming part of the gas chamber, but on a larger scale than FIGS. 1 and 2;

FIG. 4 is a view in elevation of the rear end of the piston shown in FIG. 3;

FIG. 5 is a fragmentary, top plan View of the rear of the breech block showing the longitudinally extending groove and the element for providing the lost motion connection between the slide and the breech block;

FIG. 6 is a cross sectional view of the breech block, taken along line 6--6 of FIG. 5, but on a larger scale;

FIG. 7 is a view taken along line 7-7 of FIG. l showing the rear stop for the return spring and showing part of the gun barrel and the frame of the gun;

FIG. 8 Vis a side view, partly in section of the cylinder, part thereof being shown in section, the scale being the same as in FIG. 3;

FIG. 9 is a rear view of the gun barrel looking in the direction of line 9 9 of FIG. 2;

FIG. 10 is a front view of the breech block and showing, in section, part of the slide, the cam actuating pin carried thereby and a guide spring for the breech block; and

FIG. 1l is a side view of the breech block and the guide spring therefor.

Referring generally to the drawings, the firearm is shown as a forty-five Colt automatic pistol 2f), including a main frame 22 including the grip section or stock 24 which provides the chamber for the cartridge magazine. The fore part 26 is substantially semi-circular forming an open top channel 28. The pistol includes the trigger 30, the safety grip 32, the hammer 34, the firing pin and the usual mechanism (not shown) for controlling and actuating the same.

The gun barrel 36 is fastened to the main frame 22 by a removable pin 38 which extends through a downwardly extended lug 40 which is formed integrally with the barrel. The breech end 42 of the barrel is provided with a circular groove 44 which latter is connected with rear- Wardly extending flutes 46 providing a series of grooves 48 and forwardly facing shoulders 50.

The breech block 52 is also provided with flutes 54 forming rearwardly facing shoulders S6. The flutes 54 of the breech block are adapted to register with and pass through the grooves 48 formed by the flutes 46 in the breech, and, after the flutes 54 are passed forwardly through the grooves 48 and into the circular groove 44 of the barrel, and the breech block is then turned, the shoulders 56 on the block engage the shoulders Si) of the breech. Thus the flutes 46 and 54 form locking elements for locking the block to the barrel.

The breech block 52 is adapted first to be.unlocked from the breech by rearward movement of a gas actuated part here-in shown as the slide 60; continued rearward movement of the slide effects rearward movement of the breech block 52 and the ejection of the case.

Referring more in detail to the drawings, the barrel 36 is threaded as at 62 intermediate the muzzle end 64 and the breech end for threadedly carrying a cylindrically shaped, stationary piston 66. Piston 66 is provided with an internal circularly shaped groove forming a chamber 68 which is in open communication with a series of radially extending orifices 70 disposed intermediate the breech and muzzle ends of the barrel and forwardly of the threaded section 62 about the barrel. A series of holes 72 extends rearwardly from the chamber 68 to the rear end of the piston.

A cylinder 74 is fixed to the slide 60 by two screws '76 and extends forwardly of the front end of the slide and surrounds and closely embraces the stationary piston 66. The cylinder 74 is provided with a circularly shaped shoulder 78 adjacent the rear end thereof, which, when the slide is in its foremost position, is adjacent the rear of the piston. As shown in FIG. l, the rear of the piston 66 forms a shoulder which is engaged by the shoulder 78 of the cylinder to thus limit the forward movement of the slide 60.

The lower part of the slide 60 and the upper part of the main frame 22 are provided with cooperating grooves and ridges, standard in the Colt pistol, for guiding the slide. Thus it will be understood that the expanding gas, following the projectile and entering the chamber 68 of the cylinder 64 and impinging on the cylinder 74 will cause the cylinder and slide to be moved rearwardly to first unlock the breech block 52 from the breech and thereafter move the block rearwardly.

The horizontally extending channel 28, of the fore part 26 of the main frame 22, slidably receives a semicircular section 80 which is formed integrally with and disposed below the cylinder 74. Section 80 slidably receives a cylindrical tube 82 having a closed front end 84 which is in abutting relationship with a circular ridge 86 about the cylinder 74. Tube 82 is urged forwardly against the ridge 86 by a spring 88. This spring is under compression, it being disposed between the end of the tube and a plate 90 which bears against a shoulder 92 on the main frame 22. Spring 88 receives and is guided by a rod 94 which is fixed to the plate 90. The spring 88 is further compressed when the tube 82 is moved rearwardly. Thus the spring normally yieldingly urges the tube 82, the cylinder 74, the slide 60 and the breech block 52 forwardly, the latter being urged forwardly through a shoulder 96 on the slide. Therefore, after the gaseous force is expended, that is after the slide is moved to the position shown in FIG. 2, the spring 88 returns the elements to the position shown in FIG. 1.

Referring now, particularly to FIG. 11 and to the breech block shown in FIG. 2, it will be seen that the block is provided with camming surfaces 98 and 100 which are provided by a spirally shaped groove 102 in the periphery of the block. This groove 102 receives a pin 104, the latter being fixed to the slide. Rearward movement of the slide causes the pin 104 to engage the camming surface to effect turning movement of the circularly shaped breech block, and forward movement of the slide causes the pin to effect turning movement of the breech block, through camming surface 98, in the opposite direction. The turning movement through the camming surface 100 effects unlocking of the breech block from the breech, and the turning movement through the camming surface 98 effects locking movement between the block and breech.

Referring now to FIGS. 2, 5 and 6, it will be seen that the top side of the rear of the hollow stem 105 of the breech block is provided with a longitudinally extending and coaxially curved groove 108 on the periphery thereof and adjacent the rear of the stem. This groove 108 receives a breech block moving element in the form of a screw 110 which is fixed to the slide 60. Thus the groove provides a rearwardly extending shoulder 112 and a forwardly extending shoulder 114. The screw 110 and spaced shoulders 112 provide a lost motion connection between the slide 60 and the breech block 52. Therefore, the first part of the rearward movement of the slide effects only turning movement of the block to unlock the block from the breech and after and not until the block is unlocked from the breech, the screw 110 then engages the shoulder 114 of the groove 108 to move the breech block 52 from the position shown in FIG. l to that shown in FIG. 2.

A leaf spring 116 is fixed to the inside wall of the slide 60 and this spring is received by and frictionally engages the ywalls of a groove 118 in the periphery of the breech block 52.. Therefore, due to the friction engagement aforesaid, upon reverse movement, i.e., forward movement to the left, of the slide 60, the block 52 will be moved to the left. This groove extends longitudinally of the barrel 36 and therefore guides the breech block linearily of the barrel. The fore part of this spring 116 is curved upwardly so that when it is moved forwardly and when engaging the rear of the breech of the barrel, it is moved upwardly and out of the slot 118, whereby the breech block is free to turn.

After the breech block is brought to the breech end of the barrel 36 and upon further forward movement of the slide, the pin 104 thereon enters the groove 102 and turns the breech block into locking position with breech of the barrel 36.

A spring clip 120 is fixed to the breech block 52 and the free end thereof extends forwardly of the front cartridge case abutment wall 122 of the block. The free end of the spring 120 is provided with a lip 124 which extends forwardly of the rim of the cartridge case 126 and therefore assists in retaining the case in position. A case ejector in the form of a push-rod 130 extends through an opening 132 in the breech block 52. This hole and push-rod are disposed diagonally relative to the spring clip 120. The rear end of the push-rod 130 extends rearwardly and is adapted to engage an abutment 134 on the main frame immediately prior to the extreme rearward movement of the block, whereby the front end of the push-rod 130, will engage the rear side of the spent case to cause the same to be ejected through the top opening 136 in the slide 60.

From the foregoing it is apparent that there has been provided a firearm in which the spent cartridge case is forcibly ejected. The push-rod or pin 130, upon engagement with the fixed abutment 134 provide straight line extraction of the spent case from the breech block without biased tensioning which latter is common in conventional spring loaded push-rod type ejecting devices.

Further, the design of the present invention provides for straight line operating motions that are coaxial with the fore of the barrel. Such action inherently is smooth and eliminates many sources of transient vibrations and stresses associated with more conventional types of gas operated ejector mechanisms.

Furthermore, this design also provides a dampening effect on primary recoil which is generated from the discharge of the cartridge. Firing the projectile out of the front of the barrel creates an action and therefore recoil is generated as an equal but opposite reaction. However, the impingement of gases on the gas cylinder 74 also creates an action; and, since movement of the gas actuated cylinder also moves a substantial mass of the firearm rearwardly, a significant reaction force (or secondary recoil) is developed that pushes forwardly on the piston 66. The piston 66 being fixed to the barrel 36 and the barrel, being fixed to the frame 22, the secondary recoil against the piston acts to move the frame forwardly, counteracting at least some of the primary (rearward) recoil from the discharge of the cartridge. Such features help to stabilize the firearm, causing it to be more controllable during firing.

Concentric location of operating parts around the axis of the bore makes use of the barrel as an integral struc tural member in the system, eliminating many conventional devices and appendages for attaching or supporting gas cylinders and other operating parts. Reduction in weight and size of the mechanism is accomplished. In some small weapons, such as pistols, carbines, and submachine guns, the use of this system can provide a light weight, compact, locked breech mechanism capable of tiring more powerful ammunition than most conventional designs.

The design configuration of this system makes it highly adaptable to low cost, mass production machining methods.

While the form of embodiment herein shown and described constitutes preferred form, it is to be understood that other forms may be adopted falling within the scope of the claims that follow.

I claim:

1. A iirearm comprising in combination:

(A) means forming:

(1) a frame,

(2) a gun barrel supported by the frame, said gun barrel having:

(a) a muzzle end,

(b) a breech end,

(c) an orifice between the muzzle and breech ends,

(d) a breech block locking element at the breech;

(B) means forming a chamber surrounding the gun barrel and in communication with the orifice in the barrel, said second mentioned means including:

(1) a movable part slidably carried by the first mentioned means, said movable part being movable rearwardly by expansion of gas in said chamber;

(C) a breech block slidably and turnably carried by the movable part, said breech block having:

(1) a locking element, which upon turning of the breech block, cooperates with the first mentioned locking element for locking the breech block against the breech;

(D) means actuated by said rearward movement of the movable part upon expansion of the gas in the chamber for first turning the breech block to unlock the locking element on the breech block from the locking element on the barrel and for thereafter shifting the breech block rearwardly;

(E) a spring normally urging said movable part forwardly and subsequently to the shifting of the breech block rearwardly, co-operating with the last mentioned means for shifting the breech block forwardly and for thereafter turning the breech block to lock the locking element on the breech block with the locking element on the barrel;

(F) and a shoulder on the barrel for limiting forward movement of said movable part by the spring.

2. A rearm as deiined in claim 1, characterized in that said breech block includes:

(1) a spirally shaped cam; and further characterized in that said movable part includes:

(a) a cam actuator engaging said cam for imparting spiral movement to the breech block;

and further characterized to include:

(G) means forming a lost motion connection between said movable part and the breech block.

3. A lirearm as dened in claim 1, characterized in that the means (B) forming the chamber includes:

(2) a relative stationary piston carried by the barrel.

References Cited by the Examiner UNITED STATES PATENTS 172,448 1/ 1876 Keene 42-25 1,138,376 5/1915 Hammond 89-185 2,146,743 2/1939 Johnson 89-172 2,468,784 5/1949 Seagraves 89-185 2,481,548 9/1949 Waltke 89-174 2,603,019 7/1952 Elkas 42-25 2,869,268 1/1959 Sefried et al. 42-25 2,932,108 4/1960 Hughel et al 42-25 X BENJAMIN A. BORCHELT, Primary Examiner. 

1. A FIREARM COMPRISING IN COMBINATION: (A) MEANS FORMING: (1) A FRAME, (2) A GUN BARREL SUPPORTED BY THE FRAME, SAID GUN BARREL HAVING: (A) A MUZZLE END, (B) A BREECH END, (C) AN ORIFICE BETWEEN THE MUZZLE AND BREECH ENDS, (D) A BREECH BLOCK LOCKING ELEMENT AT THE BREECH; (B) MEANS FORMING A CHAMBER SURROUNDING THE GUN BARREL AND IN COMMUNICTION WITH THE ORIFICE IN THE BARREL, SAID SECOND MENTIONED MEANS INCLUDING: (1) A MOVABLE PART SLIDABLY CARRIED BY THE FIRST MENTIONED MEANS, SAID MOVABLE PART BEING MOVABLE REARWARDLY BY EXPANSION OF GAS IN SAID CHAMBER; (C) A BREECH BLOCK SLIDABLY AND TURNABLY CARRIED BY THE MOVABLE PART, SAID BREECH BLOCK HAVING: (1) A LOCKING ELEMENT, WHICH UPON TURNING OF THE BREECH BLOCK, COOPERATAES WITH THE FIRST MEMTIONED LOCKING ELEMENT FOR LOCKING THE BREECH BLOCK AGAINST THE BREECH; (D) MEANS ACTUATED BY SAID REARWARD MOVEMENT OF THE MOVABLE PART UPON EXPANSION OF THE GAS IN THE CHAMBER FOR FIRST TURNING THE BREECH BLOCK TO UNLOCK THE LOCKING ELEMENT ON THE BREECH BLOCK FROM THE LOCKING ELEMENT ON THE BARREL AND FOR THEREAFTER SHIFTING THE BREECH BLOCK REARWARDLY; (E) A SPRING NORMALLY URGING SAID MOVABLE PART FORWARDLY AND SUBSEQUENTLY TO THE SHIFTING OF THE BREECH BLOCK REARWARDLY, CO-OPERATING WITH THE LAST MENTIONED MEANS FOR SHIFTING THE BREECH BLOCK FORWARDLY AND FOR THEREAFTER TURNING THE BREECH BLOCK TO LOCK THE LOCKING ELEMENT ON THE BREECH BLOCK WITH THE LOCKING ELEMENT ON THE BARREL; (F) AND A SHOULDER ON THE BARREL FOR LIMITING FORWARD MOVEMENT OF SAID MOVABLE PART BY THE SPRING. 